Spin and electronic excitations in $4f$ atomic chains on Au(111) substrates

Abstract

High spin systems, like those that incorporate rare-earth $4f$ elements (REEs), are increasingly relevant in many fields. Although research in such systems is sparse, the large Hilbert spaces they occupy are promising for many applications. In this work, we examine a one-dimensional linear array of europium (Eu) atoms on a Au(111) surface and study their electronic and magnetic excitations. Ab initio calculations using VASP with PBE+U are employed to study the structure. We find Eu atoms to have a net charge when on gold, consistent with a net magnetic momemt of $\simeq 3.5{\mu }_B$. Examining various spin-projection configurations, we can evaluate first and second neighbor exchange energies in an isotropic Heisenberg model between spin-$\frac{7}{2}$ moments to obtain $J_1\approx -1.2\mathrm{K}$ and $J_2\approx 0.2\mathrm{K}$ for the relaxed-chain atomic separation of $a\approx 5$ $\dot{\mathrm{A}}$. These parameters are used to obtain the full spin excitation spectrum of a physically realizable four-atom chain. The large $|J_1|/J_2$ ratio results in a highly degenerate ferromagnetic ground state that is split by a significant easy plane single ion anisotropy of $0.6$ K. Spin-flip excitations are calculated to extract differential conductance profiles as those obtained by scanning tunneling microscopy techniques. We uncover interesting behavior of local spin excitations, especially as we track their dispersion with applied magnetic fields.

References in corpus (19)

• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Quantum Communication Through an Unmodulated Spin Chain
• Trapped-Ion Quantum Computing: Progress and Challenges
• Perfect state transfer in quantum spin networks
• Reading and Writing Single-Atom Magnets
• QuSpin: a Python Package for Dynamics and Exact Diagonalisation of Quantum Many Body Systems part I: spin chains
• Spin Chains as Perfect Quantum State Mirrors
• Spin Excitations and Correlations in Scanning Tunneling Spectroscopy
• Colloquium: Atomic spin chains on surfaces
• STM Single Atom/Molecule Manipulation and Its Application to Nanoscience and Technology
• Exploring a proximity-coupled Co chain on Pb(110) as a possible Majorana platform
• Atomic spin chain realization of a model for quantum criticality
• Spin-transfer torque on a single magnetic adatom
• Wave-function hybridization in Yu-Shiba-Rusinov dimers
• GdRh${}_2$Si${}_2$: An exemplary tetragonal system for antiferromagnetic order with weak in-plane anisotropy
• Dilution effects in spin 7/2 systems. The case of the antiferromagnet GdRhIn${}_5$
• Sensing the spin of an individual Ce adatom
• Anomalous excitations of atomically crafted quantum magnets
• Competing long-range interactions and spin vector chirality in spin-chains

Cited by in corpus (1)

• Probing nonlocal correlations in magnetic rare-earth clusters